Elijah Ayolabi received a bachelor’s degree in engineering physics from Obafemi Awolowo University, Ile-Ife in 1989, a master’s degree in geophysics from the University of Ibadan in 1994 and a PhD in geophysics from the University of Ibadan in 1999. He has 25 years experience teaching seismology, general physics, well logging/formation evaluation, electrical, gravity, magnetic, and electromagnetic methods of geophysical exploration, environmental and engineering geophysics, and near-surface geophysics.
He began his career with Ogun State University in 1992 and joined the University of Lagos in 1999 as a lecturer. He became a professor in 2008. He also has been a visiting professor at The Shell Center of Excellence in Geosciences and Petroleum Engineering, University of Benin, where he served as head of academics/research advisor. He has supervised more than 100 postgraduate researches covering different aspect of geophysics which include near-surface geophysics, potential field method analysis, environmental and engineering geophysics, borehole geophysics, seismic acquisition, processing and interpretation, basin evaluation, pore pressure prediction and analysis, etc. Ayolabi has published four books, numerous book chapters, and more than 60 scientific articles in refereed journals. He is a reviewer and associate editor for many reputable geosciences journals.
He received the Nigerian Association of Petroleum Explorationists/SHELL Award for effective development of quality education in Nigerian tertiary institutions in 2002 and 2013 NAPE–AAPG Young Professional Faculty Adviser of the Year. He is an active member of NAPE, NMGS, SEG, AAPG, and EAGE.
2015 SEG Honorary Lecturer, Middle East and Africa
Near-surface geophysics: A high-fidelity tool for engineering, environmental, and hydrological problems
Near-surface geophysics plays a key role in the affairs of humankind — existence, planning, and development. The near surface is the zone between the surface and a few hundreds of meters into the earth’s crust. It refers to area on the surface of the earth with intense human impact and activities. This is the region that serves as shelter for man, and a host for manmade activities, natural occurrences, and interactive processes. This zone is important because it supports all forms of life: human, animal, and plant. It serves as a host for mineral resources as well as a reservoir for contaminants. It provides the economic base and route for human and national development. It remains the last home for human, plant, and animal bodies. Hence, the near surface is composed of materials with measurable physical properties. Near-surface geophysics relies on measurement of some physical properties to understand the structure and dynamic behavior of this zone and its environment. Although the near surface suffers from considerable heterogeneity because of complexity and rapid change in physical properties, integrated geophysical methods and advances in technology make geophysics an attractive high-fidelity tool for unravelling near-surface mysteries for human sustenance and economic growth.
This lecture will discuss the historical development, relevance, and effectiveness of near-surface geophysics in resolving various engineering and environmental problems related to surface-subsurface interactions as well as challenges with groundwater exploration and exploitation. Integration of different geophysical methods such as seismic reflection and refraction, multichannel analysis of surface waves (MASW), electrical resistivity (1D, 2D and 3D ER), electromagnetic, ground-penetrating radar (GPR), gravity and magnetics has proved to be effective in discovering causes of catastrophic engineering failures, quantifying the extent of environmental pollution, mitigating potential hazards, estimating economic mineral deposits, delineating high-yield agricultural zones, as well as assessing groundwater resources in complex geologic terrain such as basement-sedimentary transition zones.
Near-surface geophysics requires a high degree of precision, accuracy, and resolution in providing reliable information about the subsurface. The reliability of the results depends on the nature of the problem, choice of geophysical methods, interpretation models, and underlying theoretical assumptions and limitations to avoid pitfalls. The fidelity of near-surface geophysical methods in various case studies will be considered in this lecture. Several cases of integrated applications in mineral-resource evaluation and delineation, groundwater aquifer mapping in various terrains, environmental pollution assessment and quantification, engineering-site assessment, and mapping of buried utilities, cables, pipes, seepage points and subsidence will be the focus of this lecture. 2D and 3D time-dependent variations in subsurface parameters will also be considered.